That’s actually not the case and is overly simplistic. The number of casualties is not linear to the amount of artillery. There is a diminishing marginal effect for each additional increase in the amount of artillery used.
~70 percent of total casualties from land based artillery is a firmly established peer war number.
The mismatch in shells fired is likely >10:1.
Artillery lethality is growing because of increased precision guided and drone observation / correction.
Ukraine needs to stop this while some of them are still alive.